The present invention generally relates to an exterior sideview mirror assembly suitable for mounting on a vehicle and, more particularly, to an exterior sideview mirror assembly which incorporates a film applique to provide a decorative appearance to the assembly.
More recently, the trend in exterior sideview mirror assemblies has been to provide housings for the exterior sideview mirror assemblies that match the body of the vehicle. In addition, these housings are often molded with their respective mounting arms or "sails" to provide a unitary housing which exhibits enhanced aerodynamic characteristics. However, in an attempt to reduce the cost of manufacturing such assemblies, a composite assembly has been developed which includes a base housing or frame and a shell or skull cap which is mounted to the frame, for example by snap connectors. The frame is formed from an engineering plastic, typically reinforced engineering plastic, such as reinforced nylon or the like. The shell or skull cap is formed from a plastic substrate which is then painted to match the vehicle body color. The structural capacity of the housing is provided by the frame, with the shell providing a decorative covering over at least a portion of the frame so that the housing generally matches the vehicle body. In some cases, however, these sideview mirror assemblies have exhibited increased wind noise. This wind noise is generated, such as, by the gap between the decorative shell and the frame of the mirror assembly.
Various attempts have been made to minimize and/or eliminate the wind noise. One approach is to eliminate the gap between the decorative shell and the frame. However, in order to eliminate this gap, the tolerances on the respective parts must be extremely tight which adds to the expense of the sideview mirror assembly, thus effectively eliminating the savings achieved by the skull cap design. Another approach is to alter the surface topology of the decorative shell to separate the air flow over the exterior sideview mirror assembly, which reduces the noise of the wind flow.
For example, in German Pat. No. 4,039,484 to Bayerische Motoren Werke A G, a plurality of raised portions or "bumps" are provided to separate the air flow over the housing. However, these raised portions are not aesthetically pleasing to some automobile manufactures and, further, project above the assembly potentially creating a distraction to the driver. In addition, it has been found that when a discontinuity is introduced into the substrate of the skull cap (such as when it is molded into a molding tool), that the noise reduction advantages of the surface molded discontinuity is significantly reduced by the painting process since the painting process alters the surface topology of the substrate. Rather than following the surface discontinuities, the paint partially fills in the discontinuities.
More recently in copending U.S. patent application Ser. No. 09/482,199, entitled OUTSIDE SIDEVIEW MIRROR ASSEMBLY WITH REDUCED WIND NOISE, filed Jan. 12, 2000, by Leo W. Pavao and Tun-Jen Chu, commonly assigned to Donnelly Corporation, which is herein incorporated reference in its entirety, a skull cap incorporating wind noise reduction features is disclosed that uses a film to provide the desired decorative appearance but which maintains the definition of the wind noise reduction features of the skull cap so that the noise reduction features are maintained even after the skull cap is decorated.
While these decorative covers offer unique styling and assembly and, further, have resolved the wind noise problems associated with conventional skull caps, these decorative covers still increase the number of parts and hence the assembly time as compared to conventional unitary sideview mirror designs. Consequently, there is a need for an exterior sideview mirror assembly which includes a unique outer surface for matching the vehicle to which the assembly is to be mounted to provide an aesthetic appearance of the mirror assembly without the noise associated with conventional skull cap designs while reducing the number of parts.